UNIVERSITY    OF    CALIFORNIA     AGRICULTURAL    EXPERIMENT  STATION 

BENJ.    IDE    WHEELER,    President 

THOMAS    FORSYTH    HUNT,   Dean  an o  Director 

BERKELEY  H.  e.  van  norman,  vice-director  >  >o  dean 

University  Farm  schooi 


COLLEGE   OF  AGRICULTURE 


CIRCULAR  No.  195 
March,  1918 

REVISED  COMPATIBILITY  CHART  OF 
INSECTICIDES  AND  FUNGICIDES 

By  GEO.  P.  GEAY 


STOMACH  POISONS 

Acid  Lead  Arsenate 


Basic  Lead  Arsenate 
(Neutral) 


Paris  Green 


Zinc  Arsenite 


Tobacco  Infusions 


Concentrated 

Tobacco  Preparations 


FUNGICIDES 

Bordeaux  Mixture 


Lime  Sulfur 

Solution 


Sulfur 


Alkali  Sulfides 


Cyanide  Fumigation 
TRACHEAL  POISONS 


KEY  TO  CHART: 


Data  lacking: 
.Probably  dangerous 


JDangerous  combinations  ^  ^ 

.Recommended  combinations  ..,  ,      .,.    ..Probably  safe 

Doubtful  combinatious,  m  _  _   ^Doubtful 
useful  under  some  conditions 


Paste  on  a  Sheet  of  Cardboard  and  Hang  up  for  Convenient  Reference 


REVISED    COMPATIBILITY  CHART  OF   INSECTICIDES 
AND  FUNGICIDES 


The  present  high  cost  of  supplies  and  the  scarcity  of  labor  have 
brought  the  agriculturalist  face  to  face  with  many  new  problems,  not 
the  least  of  which  is  that  of  pest  control.  With  the  exception  of 
cyanide  fumigation,  the  cost  of  an  insecticide  or  fungicide  is  usually 
much  less  than  the  cost  of  its  application.  Spraying  operations  are 
often  limited  to  a  short  space  of  time  on  account  of  unfavorable 
weather.  The  tendency  to  use,  whenever  possible,  combination  sprays 
in  the  control  of  two  or  more  pests  is  thus  accentuated.  Untried  com- 
binations are  apt  to  be  made  use  of,  sometimes  with  disastrous  results 
to  fruit  and  foliage.  The  matter  of  the  compatibility,  or  incompati- 
bility, of  insecticides  and  fungicides,  therefore,  is  now  of  unusual 
interest.  In  complex  mixtures  of  this  sort  grave  chemical  or  physical 
changes  may  take  place  which  render  the  combination  wholly  unfit 
for  use.  On  the  other  hand,  the  original  ingredients  may  remain 
unchanged,  or  may  be  improved  by  their  new  associates. 

Numerous  experiments  have  been  made  to  determine  the  advisa- 
bility of  various  combination  spraj^s  and  many  of  the  results  have 
been  published  in  bulletins  of  the  U.  S.  Department  of  Agriculture, 
the  state  experiment  stations,  and  in  agricultural  journals.  These 
reports  are  so  scattered,  and  at  times  the  conclusions  of  the  various 
investigators  are  so  conflicting,  that  one  must  spend  much  time  in 
a  search  of  the  literature  before  arriving  at  a  definite  conclusion.  In 
order  to  bring  this  information  into  more  available  form  and  to  make 
it  more  easy  of  access,  it  was  condensed  into  tabular  form  and  pre- 
sented before  the  State  Fruit  Growers'  Convention  in  assembly  at 
Davis,  June  1-6,  1914.  It  is  believed  that  this  compatibility  table  and 
its  discussion  was  the  first  comprehensive  one  of  its  kind  ever  made 
public.  It  was  therefore  presented  with  no  little  hesitation,  and  was 
considered  as  a  tentative  one  only.  Some  little  publicity  was  later 
given  the  table  through  its  publication  in  at  least  six  agricultural 
publications.  Discussion  and  criticism  were  invited  so  that  if  any  of 
the  classifications  were  incorrect,  or  did  not  correspond  with  practical 
experience,  the  faults  could  be  corrected.  Since  then,  the  matter  has 
been  followed  closely,  and  minor  corrections  have  been  made  to  cor- 
respond more  closely  to  the  best  practice.  The  original  table  has  been 
simplified  and  arranged  in  the  form  of  a  circular  chart,1  and  is  now 
believed  to  be  an  accurate  reflection  of  the  best  thought  of  the  various 
investigators  who  have  worked  on  the  subject  of  compatibility  of  in- 
secticides and  fungicides.  The  accompanying  revised  chart  is  pub- 
lished in  the  hope  that  it  will  be  of  value  in  indicating  the  sprays 
which  can  be  applied  in  combination,  thus  reducing  the  cost  of  ap- 
plication one-half,  or  in  warning  of  dangers  in  apparently  harmless 
mixtures. 


i  The  writer  is  indebted  to  Prof.  C.  A.  Noren,  Oregon  Agricultural  College,  for 
suggesting  the  circular  arrangement  of  the  chart.  A  circular  chart  based  upon 
the  writer's  original  table  and  investigations  by  Mr.  W.  C.  Morris,  Hastings,  New 
Zealand,  has  been  published  in  the  New  Zealand  Journal  of  Agriculture,  vol.  XII, 
no.  3,  p.  193,  and  in  the  Fruit  World  of  Australasia,  vol.  XVIII,  no.  10,  p.  17. 


The  stomach  poisons  are  arranged  about  the  upper  left  segment 
of  the  circle,  the  fungicides  about  the  upper  right  segment,  and  the 
tracheal  poisons  (contact  insecticides,  gaseous,  liquid,  and  solid)  about 
the  lower  segment.  Lime-sulfur  solution,  sulfur,  and  the  alkali  sul- 
fides have  important  uses  both  as  an  insecticide  and  as  a  fungicide, 
consequently  the  segments  upon  which  they  are  arranged  are  made  to 
overlap,  to  indicate  their  double  utility,  and  to  avoid  duplication  and 
an  unnecessary  number  of  lines.  The  materials  listed  have  been 
strictly  confined  to  the  standard  remedies  in  common  use  in  orchard 
spray  practice.  Colored  connecting  lines  are  made  use  of  to  indicate 
the  effect  of  mixing.  The  color  scheme  of  railroad  signals  has  been 
adopted  and  is  as  follows :  red,  danger ;  green,  proceed ;  yellow,  pro- 
ceed with  caution.  The  meaning  of  the  solid  red  and  green  lines 
appears  to  need  no  further  explanation.  A  yellow  connecting  line 
is  used  to  indicate  that  mixing  is  apt  to  produce  chemical  or  physical 
changes  which  destroy  the  original  properties  or  value  of  one  or  both 
of  the  ingredients,  or  that  the  mixture  is  recommended  for  use  in  cer- 
tain sections,  but  not  in  others,  or  for  certain  specific  purposes.  The 
broken  lines  indicate  combinations  which  have  not  been  experimented 
with,  or  not  sufficiently  so  to  definitely  establish  their  status.  The 
probabilities  are,  however,  indicated  by  the  color  scheme  as  nearly  as 
can  be  judged. 

For  the  use  of  the  chart  in  connection  with  materials,  the  names 
of  which  are  not  listed  thereon,  the  following  list  of  equivalents  has 
been  arranged: 


Names  not  Listed 

Coal-tar  ' '  Dips ' ' 

Dilead  Arsenate 

Dry  Lime-sulfur 

Iron  Sulfide 

Lead  Hydrogen  Arsenate 

Liver  of  Sulfur 

Miscible  Oils 

"Neutral"  Lead  Arsenate 

Nicotine  Sulfate 

Potassium  Polysulflde 

Sodium  Polysulflde 

"Soluble"  Oils 

' '  Standard ' '   Lead  Arsenate 

Sulfide  of  Potash 

Sulfide  of  Soda 

Sulfur  Pastes,  Commercial  (as  now 
manufactured) 

Tobacco  Extracts,  Home-made 

Tobacco  Juice  or  Tea 

' '  Tri-plumbic ' '  Lead  Arsenate 

Wettable  Sulfurs,  Commercial  (as 
now  manufactured) 

Wettable  Sulfurs,  home-made  (con- 
taining glue,  flour,  or  dextrin) 


Corresponding  Compatibility 
Soap-oil  Emulsions 
Acid  Lead  Arsenate 
Lime-sulfur  Solution 
Sulfur 

Acid  Lead  Arsenate 
Alkali  Sulfides 
Soap-oil  Emulsions 
Basic  Lead  Arsenate 
Cone.  Tobacco  Preps. 
Alkali  Sulfides 
Alkali   Sulfides 
Soap-oil  Emulsions 
Acid  Lead  Arsenate 
Alkali  Sulfides 
Alkali  Sulfides 
Sulfur 

Tobacco  Infusions 
Tobacco  Infusions 
Basic  Lead  Arsenate 
Sulfur 

Sulfur 


